Warfarin therapy as an adjunct to the surgical treatment of malignant tumors in mice.

Warfarin anticoagulation throughout the pre-, intra-, and early postoperative periods significantly improved the longterm survival and the cure rate following amputation of a well-established primary tumor. In the case of the tumor system with the more virulent metastatic spread, the T241 sarcoma in C57BL/6N mice, the increase in the cure rate was seven-fold or 8% to 55%. In the C3H/HeN mice with mammary adenocarcinoma, the increase in the cure rate was from 29% to 53%. The weight of the primary tumor-bearing limb was also significantly reduced in the Warfarin-treated mice. The level of anticoagulation producing this improvement was not excessive, with the prothrombin time prolonged between 2.8 and 3.5 times the normal, average value. Deaths from complications were increased in the Warfarin-treated mice, but not nearly to the extent that deaths with metastatic disease were reduced.